A conventional wire harness having a plurality of unshielded electric wires and a metallic shield pipe, the plurality of the unshielded electric wires being passed through the metallic shield pipe, is disclosed in Patent Document 1. According to this disclosure, the shield pipe fulfills electromagnetic shield and protection for electric wire, thereby providing a simple structure of the wire harness even with using the unshielded electric wires.
However, the conventional wire harness having the shield pipe which fulfills the electromagnetic shield function has a problem as explained below, due to an air layer existing between the shield pipe and the unshielded electric wire. That is, when applying current, heat generated at the unshielded electric wire is shielded by the air having low thermal conductivity so the generated heat is less transferred to the shield pipe. In addition, since the shield pipe does not include a ventilation pathway for ventilating air, the heat generated at the unshielded electric wire remains inside of the shield pipe, lowering the heat-release performance.
Patent Document 2 discloses a technology for dealing with the above-described problem. In Patent Document 2, there is disclosed a wire harness having a structure which prevents heat from remaining inside of the shield pipe and which improves the heat-release performance. Specifically, there is provided a resin layer which is wrapped around an outer circumference of the unshielded electric wire. Thus, when the resin layer is in contact with an inner circumference of the shield pipe, the heat generated at the unshielded electric wire can be transferred to the shield pipe and can be released from the shield pipe.